The present invention relates to an imaging apparatus having a posture detector and a power saving function, an imaging method, and a program to execute the imaging method.
An imaging apparatus such as a digital camera or the like that records a digital image by an image sensor such as a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) has a display device such as an LCD or a viewfinder that displays an image of a photographic subject. And the imaging apparatus displays an image of an object to be imaged (photographic subject) or an image recorded in a memory (recording medium), which is recognized visually by a user.
Many of imaging apparatuses having such a display device have an auto power off function, which turns off the power of the imaging apparatus, to avoid wasteful power consumption, in a case where the imaging apparatus is not operated for a certain time (generally, for about a few minutes).
Thus, wasteful power consumption is suppressed by turning off the power of the imaging apparatus while the imaging apparatus is not used by the user.
However, in a case of imaging after the power of the imaging apparatus is turned off by the auto power off function, it is necessary to turn on the power of the imaging apparatus again and perform a setting for imaging, and therefore, there is a possibility of losing a chance for imaging if the auto power off function is frequently operated.
On the other hand, there is an imaging apparatus having a power saving function that is controlled by the posture detector such that in a case where a posture of the imaging apparatus is not changed, brightness of an LCD or a viewfinder is decreased, or a power saving state where nothing is displayed is set, and in a case where the posture of the imaging apparatus in the power saving state is changed, display of the LCD or the viewfinder is returned from brightness of display in the power saving state to brightness of display in a normal state.
It is possible to decrease wasteful consumption of a battery by the above-described power saving function, because the power consumption of the LCD or the viewfinder is large.
In the above power saving function, a condition for determination of on/off of the power saving function is determined by a threshold value that determines a duration for obtaining posture information and detection of movement by the posture detector.
At this time, in a case where the duration for obtaining posture information is short, the response speed with respect to a change of posture is fast. However, though response with respect to an existence or non-existence of the change of posture is fast, this excessive response with respect to the change of posture causes repeat of the power saving state and the normal state, and therefore it is difficult to see the display of the LCD or the viewfinder. Additionally, it is difficult to differentiate a slow posture change and an output noise from the posture detector, and there is a possibility of mistaking determination of power saving.
On the contrary, in a case where the duration for obtaining posture information is long, a difference value from data obtained immediately before becomes large, therefore, it is easy to differentiate the change of posture and the output noise from the posture detector (sensor), and it is difficult for the repeat of the power saving state and the normal state to occur alternately, because the duration for movement determination is long. However, in a case where there is a drastic change of the posture of the imaging apparatus, even though it is desired to return from the power saving state to the normal state, returning from the power saving state to the normal state is slow, and there is a problem such that a user has to operate the imaging apparatus in the power saving state where it is difficult to see a display screen.
Therefore, as described above, it is inconvenient to a user in any cases.
In Japanese Patent number 4328697, in order to provide an imaging apparatus having a power saving function to avoid wasteful power consumption, an imaging apparatus is disclosed, including: a timer for an auto power off; a timer to change to a power saving mode (power saving state); an operating device to operate an imaging apparatus; and a detector to detect a change of posture of the imaging apparatus such that in a case where the operating device is operated, the timer for the auto power off and the timer to change to the power saving mode are reset, and in a case where the change of posture of the imaging apparatus is detected, only the timer to change to the power saving mode is reset. Thus, it is possible to suppress power consumption by having an auto power off function and the power saving function.
However, in Japanese Patent number 4328697, there is no specific detecting method of the change of posture, and the operability of the imaging apparatus is not efficiently improved. And, in addition, because the imaging apparatus has a plurality of timers, there is a problem of an increase in cost.